To ventilate an attic space, it is common to form a ridge slot in the roof deck extending along a ridge of the roof and to install a ridge vent over the ridge slot in conjunction with installation of soffit ventilation. The ridge vent permits heated air from the attic below to pass through the ridge slot and through the vent while preventing ingress of water, insects, and vermin into the attic. One common type of ridge vent is the so-called rollable mesh ridge vent. One rollable mesh ridge vent that has been commercially successful is the ridge vent and system disclosed in U.S. Pat. No. 5,167,579 of Rotter entitled Roof Vent of Synthetic Fiber Matting. This patent is hereby incorporated fully by reference. Generally, the Rotter ridge vent is a unitary sheet construction of randomly aligned synthetic fibers that are opened and blended, randomly aligned into a web by airflow, joined by phenolic or latex binding agents, and heat cured to produce an air-permeable mat with a substantially constant fiber density throughout. The vent is fabricated in substantial lengths and is rolled into a roll for storage and shipment. For installation, the vent is unrolled along a roof ridge covering a ridge slot and secured to the roof decking on either side of the slot. Ridge cap shingles are then installed atop the ridge vent to form a moisture barrier and to present a traditional appearance. Warm air from the attic below passes through the ridge slot, flows through the mesh mat of the ridge vent, and exits along the edges of the ridge vent to ambience.
While the Rotter ridge vent has proven successful, it nevertheless requires that a water sealed row of ridge cap shingles be carefully installed atop the vent to prevent leakage through the mat and into an attic below. There have been attempts to make mesh ridge vents with their own water barriers so that ridge cap shingles either are not required or careless installation of ridge cap shingles is less likely to result in a water leak. U.S. Pat. No. 7,422,520 of Coulton et al., for example, discloses a roof ridge vent having a covering and a method of installing a ridge vent. The. Coulton et al. ridge vent has a ventilation component comprising a mat of openwork fibers similar to the Rotter ridge vent and a waterproof membrane bonded directly to one side of the ventilation component. The Coulton et al. vent is shipped in spiral wound rolls and is rolled out along a roof ridge having an open ridge slot with the membrane facing up. The ridge vent can then be attached with fasteners to the roof deck with the membrane left exposed to provide a moisture barrier. Alternatively, ridge cap shingles can be applied over the membrane if desired. The Coulton et al. patent is hereby fully incorporated by reference.
A need exists for rollable mesh attic vents and ridge vents in particular that provide exceptional ventilation of an attic space below using less material than traditional mesh ridge vents and that can incorporate an substantially impervious water barrier to prevent rain water from passing through the thickness of the mat. It is to the provision of ridge vents that address these and other needs and that provides other advantages that the present invention is primarily directed.